Gas Disks and Supermassive Black Holes in Nearby Radio Galaxies

are described in Appendix A of van der Marel (1997) and were performed using Gauss-
Legendre integration. A Gaussian is then fitted to each observed velocity profile. In
this way we produce three model data sets (with three different black hole masses)
that we may directly compare to the observed velocity data from Chapter 3.
Some weaknesses exist in the modeling methodology we have adopted, particu-
larly in the manner in which the flux profile across the slit is accounted for. These are
discussed more fully by van der Marel & van den Bosch (1998) and Verdoes Kleijn
et al. (2002b), and some improvements that may be made are discussed (and imple-
mented) by Barth et al. (2001). However, these factors are small compared to the
smoothness of the observed velocity profiles, so we need not concern ourselves with
these details in our discussions here. Because of the unsettled nature of much of the
observed velocity profiles we feel that it would be inappropriate to attempt to find
‘best fitting’ models, when we do not understand the majority of the motions in the
gas.
4.2.5 Locating the zero point velocities
In order to compare the observed velocity field to the model predictions we must
also account for the recessional velocity of the galaxy in the observations. The mean
recessional velocity of the galaxy may vary somewhat from the mean value from
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